Stabilization of motor fuels



resinous products. The most common type of compounds, which have beenemployed for this.

Patented Feb 116,1937

- UNITED STATES PATENT bas cs v s'ranmza'non or Moron Frederick Baxterand Richard Geese Carneys Point, N. I Glarkson and aasignors, by memoassignments, to Gasoline Antioxidant Company, Wilmington, Del, 1 Icorporationoflielaware I No Drawing. Application September at, 1933,

- ScrialNo. 690,418

. 1'; claims.

This invention i elates to the stabilization of motor fuels comprisingcracked hydrocarbon spirits such as cracked gasoline and motor benzol.It is well known that motor fuels. comprising cracked. hydrocarbonspirits normally tend. to

form-gummy and resinous products upon storage, which products are highlyobjectionable. Cracked gasoline particularly is subject to this form'ofdeterioration. Also, motor fuels such as motor benzol are producedcontaining cracked hydrocarbon spirits which also tend to form" gummyand resinous products. Motor fuels comprising cracked hydrocarbonspirits have been treated by various means to remove the crackedspirits. This has been found to be objectionable for motor fuels to beused inpresent day automotive internal combustion-engines. Accordingly,it'has been suggested to add to such motor fuels various compounds whichwill inhibit or retard the formation of gummy and purpose, are thephenolic and amino compounds. The phenolic type of compounds havegenerally been preferred because the'amino type usually discolor themotor fuelor accelerate discoloration thereof. The phenolic type ofcompound, how- 'ever, is generally objectionable due to its lowsolubility and its corrosive characteristics. It has been proposed toemploy amino hydroxy 1 compounds to obtain the advantages of both thephenolic and amino compounds without their disadvantages. This. lastexpedient has not proved to be entirely satisfactory as the aminophenols, such as para-amino-phenol, are insufllciently soluble in thegasoline and also tend to discolor upon storage. It has been proposed toemploy substituted amino-phenols,in order. to

overcome the disadvantages of compounds such ,as para-amind-phenol. Thislast expedient has met with some degree of success. latter compounds, asa general rule, tend to discolor the motor fuel on storage to someextent over extended periods of time.

An object of the present invention isto provide new compounds to beemployed for stabilizing motor fuels comprising cracked hydrocarbonspirits'which compounds are exceedingly effective for preventing theformation of gum in the motor fuels and do not'discolor the motor fuelsduring storage; A further object is to'provide.

improved methods for stabilizing motor fuels comprising crackedhydrocarbon spirits. Another object is to provide motor fuels comprisingcracked hydrocarbon spirits which do not discolor and in which thetendency to form gum is greatly inhibited. Still other objects are toprovide new compositions of matter and'to ad- ,vance the'art. Otherobjects will appear herein- However. these (oi. u- -si' These obiectsmay accomplished in accordance with our invention which comprisesincorporating' in motor fuels comprising cracked hydrocarbon spirits,suchas cracked gasoline and.

motor benzol, a compound of the type:

-'- (Hie-OH:

aliphatic hydrocarbon group in which at least one 2 hydrogen issubstituted by an aryl nucleus.

Among the compounds which we have found to be particularly satisfactoryfor our purpose are p-hydroxy N-phenyl morpholine, 4-hydroxy-2-methyi-N-phenyl morpholine and 4-hydroxy-3-' methyl-N-phenyl morpholine.Methods of making compounds of this type are disclosed in the patentto'I-Iorace B. Pray, No. 2,063,191. Briefly, the hydroxy arylmorpholines are prepared by heating an aminophenol with beta betadichlor ethyl ether in the presence of water and a mild inorganic alkalisuch as magnesium hydroxide,

magnesiumoxide, calcium carbonate,'zinc oxide and the like under'slightsuperatmospheric pressure. The hydroxy aryl morpholine I obtained willbe the one corresponding with the aminophenol employed. These compoundsare insoluble in water and will precipitate from the,

solution and can be easily separated therefrom.

. The eifectiveness of these compounds asantigumming agents was testedessentially according a to the method proposed by Voorhees and Essingerin J. S. A. E. 24, 584 (1929). In this test, cc.

of the motor fuel is heatedin a glass flask under an oxygen atmosphereat 100 C. The flask is connected to a mercury manometer and-the pressure observed at regular intervals. The elapsed time, from the start ofthe test until the motor fuel begins to absorb oxygen, as shown by thefall of the pressure, is known as the "induction peri- 0d of the fuel.The effectiveness of an anti-- gumming' agent or gum inhibitor ismeasured by the increase'in the induction period caused.

by the addition of a known amount of inhibitor.

.That the inductionperiod is directly related to gum formation can beshown by heating a control sample of gasoline, containing no inhibitor,

beyond its induction-period and a second sample a v of gasoline,containing the inhibitor, for the same'length of time and determiningthe gum formed in each case by evaporating the gasoline samples in tareddishes in an inert atmosphere. The residue is the gum formed in eachcase.

As is well known to those skilled in the art, p-aminophenol, under theabove test conditions, gives very satisfactory results. The use of thiscompound is not, however, commercially practiv 0.003% by weight calsince its solubility, at ordinary temperatures, is insufficient topermit the use of a suiiicient amount of the compound. Moreover,gasoline, containing p-aminophenol, is rapidly discolored under theaction of light and air.

Wehave now found that the hydroxy N-aryl morpholines and particularlythe p-hydroxy N-phenyl morpholines and the o-hydroxy N-phenylmorpholines are free from these disadvantages, Their solubility ingasoline is suflicient to permit the use of the quantity required togive an effective stabilization of the gasoline and their solutions ingasoline do not become colored during storage over extended periods oftime.

In order to more clearly illustrate our invention and the advantageousresults to beobtained thereby, the following examples are given:

Example 1 A gum-free unsaturated gasoline, containing 0.002% by weightof p-hydroxy N phenyl morpholine, had an induction period of 270minutes,when subjected to the above described test. A control sample of the samegasoline, containing no inhibitor, had an induction period of only 60minutes, under the same conditions.

Erample 2 A gum-free unsaturated" gasoline, containing pholine, had aninduction period of 460 minutes,

as determined by the above test. The control sample, without riod,ofonly .60 minutes.

During this last test, samples 'of gasoline were withdrawn at the end of240 minutes and evap- 'orated in a .steam oven in tared dishes. Theweight of gum, obtained from the uninhibited sample, was 246 mg. from 25cc. of gasoline. The weight of gum, obtained from the inhibited sampie,was 3 mg. from 25 cc. of gasoline.

, Example 4 Example 3 A gum-free unsaturated gasoline, containing 0.003%by weight of 4-hydrom-2-methyl-N-phenyl morpholine, had an inductionperiod of 130 minutes. The control sample gave 70 minutes, underthe'same conditions.

-A gum-free unsaturated gasoline, containing 0.003% by weight or4-hydroxy-3=methyl-N-phemorpholines should also be mentioned. Othercompounds within the class which may be mentioned are:4-methy1-2-hydroxy-N-phenyl morpholine, 3-butyl-2-hydroxy-N-phenylmorphoof p-hydroxy N-phenyl morinhibitor, had an induction pe'- line,4-hydroxy-N-phenyl-3-5-dimethyl morpholine. I

The aryl group may also contain 2 or 3 hydrocarbon substituents whichmay be alike or diflerent;

The amounts of the gum inhibitors, which it is necessary to employ, willvary with the nature and concentration of the unsaturated constituentsof the motor fuel and the degree of stabilization it is desired toobtain. In general, however, the concentration of inhibitor in the motorfuel will be substantially less than 0.1 by weight.

From all of the above, it will be apparent that we have discovered a newclass of compounds which are very emcient gum inhibitors, which aresufflciently soluble in gasoline to be readily utilized, and which donot cause noticeable discoloration of the motor fuel in aging.

While we have disclosed certain specific embodiments of our inventionand the preferred modes of carrying the same into effect, it will bereadily apparent to those skilled in the art that many variations andmodifications may .be made therein without departing from the spirit ofour invention. Accordingly, the scope of our invention is to be limitedsolely by the appended claims construed as' broadly as of the prior art.

We claim:

1. Motor fuel comprising cracked hydrocarbon spirits normally tending toform gummy substances on storage having incorporated therein, in anamount suilicient to inhibit the formation of the gummy substances, 9.compound of the GHQ-CH1 wherein It represents an aryl nucleus.

is permissible in view 3 2. Motor fuel comprising cracked hydrocarbonspirits normally tending to form gummy sub-' stances on storage havingincorporated therein,

in an amount suflicient to inhibit the formation of the gummysubstances, 8. compound of'the type:

Clif -CHI HO-R-N y I I CHrG z wherein R represents a phenyl nucleus.

3. Motor fuel comprising cracked hydrocarbon spirits normally tending toform gummy substances on storage having incorporated therein, in anamount suflicient to inhibit the formation r of thegummy substances, acompound of the CHr-CH! wherein R represents an aryl nucleus havingsubstituted therein at least one member of the group consisting ofalkyl, alkaryl and aryl groups.

- Ho-n-N o era-cm wherein' R. represents a phenyl nucleus havingsubstituted therein at least one member of the group consisting ofalkyl, alkaryl and aryl groups.

5. Motor fuel comprising cracked hydrocarbon spirits normally tending toform gummy substances on storage having incorporated therein, in anamount sufficient to inhibit. the formation of the gummy substances, acompound of the type: I

/CHl'CHs HO-RN\ car-cm wherein R represents an aryl nucleus and whereinthe hydroxy group is para to the morpholine radical.

6. Motor fuel comprising cracked'hydrocarbon spirits normally tending toform gummy substances on storage having incorporated therein, in anamount sufllcient to inhibit the formation of the gummy substances, acompound of the type:

CHr-CH,

wherein R represents a phenyl nucleus and wherein the hydroxy group ispara to the morpholine radical.

7. Motor fuel comprising cracked hydrocarbon spirits normally tending toform gummy substances on storage having incorporated therein, in anamount sufllcientto inhibit the formation of the gummy substances, acompound of the typ CHr-CKK carom wherein R represents a phenyl nucleushaving substituted-therein at least one member of the group consistingof alkyl, alkaryl and aryl groups and wherein-the hydroxy group is parato the morpholine radical. g

8. Cracked gasoline normally tending to'form gummy substances ,onstorage having incorporated therein, in an amount sumcient to inhibitthe formation of the gummysubstances, a compound of the type:

CHI-CHI no-no CHrCHI wherein R represents an aryl nucleus.

9. Cracked gasoline normally tending to form gummy substances on storagehaving incorporated therein, in an amount sui'iicient to inhibit theformation of the gummy substan a compound of the type:

CHI-C no-no I CHr-CHs I wherein -R represents a phenyl nucleus.

10. Cracked gasoline norm lly-tendin to form" gummy substances onstorage having incorporated therein. in an amount suiiicient to inhibitthe formation of the gum substance a compound of the typ i V OKs-CH4 vno-n--n o wherein R represents an: aryl nucleus ha lisdroxy sufilcientto retard the formation of said gummy substances.

substituted therein at least one member of the groupconsisting of alkyl,alkaryl and aryl groups.

11. Cracked gasoline normally tending to form gummy substances onstorage having incorporated therein, in an amount suiilclent to inhibitthe formation of thegummy substances, a compound of the type: i I

. OHr-OHs HOB-N\ o OKs-CH:

wherein R represents a phenyl nucleus having substituted therein atleast one member of the group consisting of alkyl, alkaryl and arylgroups.

12. Motor benzol normally tending to form gummy substances on storagehaving incorporated therein, in an amount sufllcient to inhibit theformation of the substances, a compound of the type:

ca -oa wherein R represents an aryl nucleus.

13. Motor benzol normally tending to form gummy substances -onstorage'having incorporated therein, in an amount suflicient to inhibitthe formation of the gummy substances, a compound of the type:

BIO-11- OKs-Cling OKs-CH1 R represents a phenyl nucleus.

benzol normally tending'toform storage having incorposufllcient toinhibit wherein 14. Motor gummy substances on rated therein, in anamount the formation of the gummy substances, a compound of the type:

on on, no-n-rr 0 CHr-CH! v u wherein R represents an aryl nucleus havingsubstituted therein at least one member of the group consisting ofalkyl, alkaryl and aryl groups.

- 15. Motor benzol normally tending to form gummy substanceson storagehaving incorporated therein, in an amount sufficient to inhibit theformation of pound of the type: v a

I CHs-CH!\ OBPCHQ/ N-phenyl morpholine mans-men nsx'rm nowsma. mcnsnnoases cnsnxson'.

the gummy substances, a com-

